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[PATCH 1/4] perf record: Use %ld for long type sample counter

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  [PATCH 1/4] perf record: Use %ld for long type sample counter He Kuang <hekuang@huawei.com> - 2015-07-01 11:10 +0200
    [PATCH 4/4] perf probe: Add failure check when show variable range He Kuang <hekuang@huawei.com> - 2015-07-01 11:10 +0200
    [PATCH 3/4] perf probe: Enable --range option according to libdw version He Kuang <hekuang@huawei.com> - 2015-07-01 11:10 +0200
    [PATCH 2/4] perf probe: Fix failure to probe online module He Kuang <hekuang@huawei.com> - 2015-07-01 11:10 +0200

#1175103 — [PATCH 1/4] perf record: Use %ld for long type sample counter

Since we post-process and count (long rec->samples) to show precise
number of samples instead of estimate on (u64 rec->bytes_written), the
format string of that should be changed to %ld accordingly, otherwise
the value don't show right on 32bit machine.

Before this patch:

  $ perf record -e syscalls:sys_enter_write -- dd if=/dev/zero
  of=/dev/null bs=4k count=1000
  1000+0 records in
  1000+0 records out
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.077 MB perf.data (1 samples) ]

After this patch:

  $ perf record -e syscalls:sys_enter_write -- dd if=/dev/zero
   of=/dev/null bs=4k count=1000
  1000+0 records in
  1000+0 records out
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.077 MB perf.data (1001 samples) ]

Signed-off-by: He Kuang <hekuang@huawei.com>
---
 tools/perf/builtin-record.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index de165a1..65e632d 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -737,7 +737,7 @@ out_child:
 
 		if (rec->samples && !rec->opts.full_auxtrace)
 			scnprintf(samples, sizeof(samples),
-				  " (%" PRIu64 " samples)", rec->samples);
+				  " (%ld samples)", rec->samples);
 		else
 			samples[0] = '\0';
 
-- 
1.8.5.2

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#1175104 — [PATCH 4/4] perf probe: Add failure check when show variable range

Change improper type size_t to diffptr_t to make consistent with libdw
and handle error code.

Signed-off-by: He Kuang <hekuang@huawei.com>
---
 tools/perf/util/dwarf-aux.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 2cb4c82..da96eb1 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -965,7 +965,7 @@ static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
 {
 	Dwarf_Die *scopes;
 	int count;
-	size_t offset = 0;
+	ptrdiff_t offset = 0;
 	Dwarf_Addr base;
 	Dwarf_Addr start, end;
 	Dwarf_Addr entry;
@@ -991,6 +991,9 @@ static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
 
 	while ((offset = dwarf_ranges(&scopes[1], offset, &base,
 				&start, &end)) > 0) {
+		if (offset < 0)
+			goto out;
+
 		start -= entry;
 		end -= entry;
 
@@ -1029,7 +1032,7 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
 	Dwarf_Addr entry;
 	Dwarf_Op *op;
 	size_t nops;
-	size_t offset = 0;
+	ptrdiff_t offset = 0;
 	Dwarf_Attribute attr;
 	bool first = true;
 	const char *name;
@@ -1048,6 +1051,9 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
 	while ((offset = dwarf_getlocations(
 				&attr, offset, &base,
 				&start, &end, &op, &nops)) > 0) {
+		if (offset < 0)
+			return offset;
+
 		if (start == 0) {
 			/* Single Location Descriptions */
 			ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
-- 
1.8.5.2

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#1175109 — [PATCH 3/4] perf probe: Enable --range option according to libdw version

The option --range uses functions in libdw (elfutils version >= 1.57),
this patch check if elfutils version meets the requirements before
enable this feature, so that perf can be built with old libdw.

Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: He Kuang <hekuang@huawei.com>
---
 tools/perf/builtin-probe.c  |  2 ++
 tools/perf/util/dwarf-aux.c |  2 ++
 tools/perf/util/dwarf-aux.h | 13 ++++++++++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 1272559..2760c06 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -372,8 +372,10 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
 		     "Show accessible variables on PROBEDEF", opt_show_vars),
 	OPT_BOOLEAN('\0', "externs", &probe_conf.show_ext_vars,
 		    "Show external variables too (with --vars only)"),
+#if _ELFUTILS_PREREQ(0, 157)
 	OPT_BOOLEAN('\0', "range", &probe_conf.show_location_range,
 		"Show variables location range in scope (with --vars only)"),
+#endif
 	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
 		   "file", "vmlinux pathname"),
 	OPT_STRING('s', "source", &symbol_conf.source_prefix,
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 57f3ef4..2cb4c82 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -950,6 +950,7 @@ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
 	return 0;
 }
 
+#if _ELFUTILS_PREREQ(0, 157)
 /**
  * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
  * @sp_die: a subprogram DIE
@@ -1071,3 +1072,4 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
 
 	return ret;
 }
+#endif /* _ELFUTILS_PREREQ(0, 157) */
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index c42ec36..ade0c50 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -125,6 +125,17 @@ extern int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf);
 
 /* Get the name and type of given variable DIE, stored as "type\tname" */
 extern int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf);
+#if _ELFUTILS_PREREQ(0, 157)
 extern int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
-			struct strbuf *buf);
+			     struct strbuf *buf);
+#else
+static inline
+int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
+		      Dwarf_Die *vr_die __maybe_unused,
+		      struct strbuf *buf __maybe_unused)
+{
+	return -ENOTSUP;
+}
+
+#endif /* _ELFUTILS_PREREQ(0, 157) */
 #endif
-- 
1.8.5.2

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#1175112 — [PATCH 2/4] perf probe: Fix failure to probe online module

Kernel module has the type DSO_TYPE_USER, the check on dso type in
kernel_get_module_dso() disable openning debuginfo of online kernel
modules.

Problem can be reproduced as:

  $ insmod test_bpf.ko

  $ perf probe -v -m test_bpf --add='skb_is_nonlinear'

  probe-definition(0): skb_is_nonlinear
  symbol:skb_is_nonlinear file:(null) line:0 offset:0 return:0 lazy:(null)
  0 arguments
  Failed to find module test_bpf.
  Could not open debuginfo. Try to use symbols.
  Failed to find symbol skb_is_nonlinear in test_bpf
    Error: Failed to add events. Reason: No such file or directory (Code: -2)

Infact kernel_get_module_dso() function is called in perf-probe, in this
condition, machine->dsos list contains only dsos which is either kmod or
kernel loaded by machine__create_kernel_maps(), so there's no need to
pick away the non-kmod user type dsos.

This patch removes the check.

After this patch:

  $ perf probe -v -m test_bpf --add='skb_is_nonlinear'

  probe-definition(0): skb_is_nonlinear
  symbol:skb_is_nonlinear file:(null) line:0 offset:0 return:0 lazy:(null)
  0 arguments
  Open Debuginfo file: /lib/modules/4.1.0+/test_bpf.ko
  Try to find probe point from debuginfo.
  Matched function: skb_is_nonlinear
  found inline addr: 0x10ab3
  Probe point found: test_bpf_init+585
  Found 1 probe_trace_events.
  Opening /sys/kernel/debug/tracing/kprobe_events write=1
  Added new event:
  Writing event: p:probe/skb_is_nonlinear test_bpf:test_bpf_init+585
    probe:skb_is_nonlinear (on skb_is_nonlinear in test_bpf)

  You can now use it in all perf tools, such as:

      perf record -e probe:skb_is_nonlinear -aR sleep 1

Signed-off-by: He Kuang <hekuang@huawei.com>
---
 tools/perf/util/probe-event.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 381f23a..8ad2743 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -275,8 +275,6 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso)
 
 	if (module) {
 		list_for_each_entry(dso, &host_machine->dsos.head, node) {
-			if (!dso->kernel)
-				continue;
 			if (strncmp(dso->short_name + 1, module,
 				    dso->short_name_len - 2) == 0)
 				goto found;
-- 
1.8.5.2

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